1. Field of the Invention
One embodiment of the present invention relates to a manufacturing method of a semiconductor device including an oxide semiconductor film.
Note that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. In addition, one embodiment of the present invention relates to a process, a machine, manufacture, or a composition of matter. In particular, one embodiment of the present invention relates to a semiconductor device, a display device, a liquid crystal display device, a light-emitting device, a power storage device, a memory device, a driving method thereof, or a manufacturing method thereof.
2. Description of the Related Art
Attention has been focused on a technique for forming a transistor using a semiconductor thin film formed over a substrate having an insulating surface (also referred to as a field-effect transistor (FET) or a thin film transistor (TFT)). Such transistors are applied to a wide range of electronic devices such as an integrated circuit (IC) and an image display device (display device). A semiconductor material typified by silicon is widely known as a material for a semiconductor thin film that can be used in a transistor. As another material, an oxide semiconductor has been attracting attention (e.g., Patent Document 1).
Furthermore, for example, Patent document 2 discloses a semiconductor device in which, to reduce oxygen vacancies in an oxide semiconductor layer, an insulating layer which releases oxygen by heating is used as a base insulating layer of the oxide semiconductor layer where a channel is formed.
In addition, a method for manufacturing a semiconductor device in which an oxide semiconductor layer is highly purified in the following manner is disclosed: an oxide insulating layer is formed over the oxide semiconductor layer; oxygen is introduced (added) through the oxide insulating layer; heat treatment is performed; and impurities such as hydrogen, moisture, a hydroxyl group, or hydride are removed from the oxide semiconductor layer by the introduction of oxygen and the heat treatment (e.g., Patent Document 3).